http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/414 Wed, 22 May 2013 15:32:39 GMT 2013-05-22T15:32:39Z http://dyuthi.cusat.ac.in:80/xmlui/bitstream/id/696/CATZFLK8.jpg http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/414 http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2979 Synthesis, characterization and kinetic studies on complex formed between amantadine hydrochloride and sodium molybdate at physiological pH Sridevi, N; Yusuff, K K Mohammed The title reaction was undertaken to establish the interaction between amantadine and molybdate at physiological pH. Identical FTIR spectra, TG-DTA curves and CHN data of the complexes formed from three solutions at pH 1.5, 7.4 and 8.0 indicate that the same complex was formed at all the three pHs. The FTIR spectrum shows shift in peaks corresponding to primary amino group of the drug due to coordination to molybdate. An octahedral geometry is assigned to the complex. The kinetics of the complexation has been studied at low concentrations of the reactants using UV-visible spectrophotometry. At pH 7.4, the initial rate varies linearly with [molybdate]. A plot of initial rate versus [drug] is linear passing through origin. These results indicate that the drug and molybdate react at pH 7.4 even at low concentrations. At pH 1.5, the rate increases linearly with increase in [drug] but decreases with [molybdate]. The effect of pH and ionic strength on the rate of the reaction has also been studied. A suitable mechanism has been proposed for the reaction. Reaction between the drug and molybdate even at low concentrations and the fact that the amino group of amantadine required to be free for its function as antiviral, is bound to molybdate in the complex suggests that simultaneous administration of the drug and molybdate supplements should be avoided. Tue, 01 Jan 2008 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2979 2008-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2322 Vanadia supported on ceria: Characterization and activity in liquid-phase oxidation of ethylbenzene Radhika, T; Sugunan, S Vanadia/ceria catalysts (2–10 wt% of V2O5) were prepared by wet impregnation of ammonium metavanadate in oxalic acid solution. Structural characterization was done with energy dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), BET surface area measurements, FT-IR spectroscopy and nuclear magnetic spectral analysis (51V MASNMR). XRD and 51V MASNMR results show highly dispersed vanadia species at lower loadings and the formation of CeVO4 phase at higher V2O5 loading. The catalytic activity of catalysts was conducted in liquid phase oxidation of ethylbenzene with H2O2 as oxidant. The oxidation activity is increased with loading up to 8 wt% V2O5 and then decreased with further increase in V2O5 content to 10 wt%. Different vanadia species evidenced by various techniques were found to be selective towards ethylbenzene oxidation. The CeVO4 formation associated with increased concentration of vanadia on ceria results the production of acetophenone along with 2-hydroxyacetophenone. Thu, 01 Feb 2007 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2322 2007-02-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2321 Influence of surface and acid properties of vanadia supported on ceria promoted with rice husk silica on cyclohexanol decomposition Radhika, T; Sugunan, S Cyclohexanol decomposition activity of supported vanadia catalysts is ascribed to the high surface area, total acidity and interaction between supported vanadia and the amorphous support. Among the supported catalysts, the effect of vanadia over various wt% V2O5 (2–10) loading indicates that the catalyst comprising of 6 wt% V2O5 exhibits higher acidity and decomposition activity. Structural characterization of the catalysts has been done by techniques like energy dispersive X-ray analysis, X-ray diffraction and BET surface area. Acidity of the catalysts has been measured by temperature programmed desorption using ammonia as a probe molecule and the results have been correlated with the activity of catalysts. Tue, 01 Aug 2006 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2321 2006-08-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2320 Sulfated titania mediated regioselective nitration of phenol in solid state Sunajadevi, K R; Sugunan, S Titania, sulfated titania and chromium loaded sulfated titania were prepared by sol–gel method and characterized using different technique. Phenol is nitrated regioselectively by nitric acid using chromium loaded sulfated titania catalysts. A remarkable ortho selectivity is observed in solid state nitration to yield exclusively ortho-nitrophenol. Compared to the conventional process, phenol nitration over solid acid catalyst is a clean and environment friendly process. Catalytic activity well correlates with the Brönsted acid sites of these catalysts. Thu, 01 Sep 2005 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/2320 2005-09-01T00:00:00Z